Framework for EVPN Designated Forwarder Election Extensibility
draft-ietf-bess-evpn-df-election-framework-06

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BESS Workgroup                                           J. Rabadan, Ed.
Internet Draft                                                     Nokia
                                                         S. Mohanty, Ed.
Intended status: Standards Track                              A. Sajassi
                                                                   Cisco
                                                                J. Drake
                                                                 Juniper
                                                              K. Nagaraj
                                                            S. Sathappan
                                                                   Nokia

Expires: June 7, 2019                                   December 4, 2018

     Framework for EVPN Designated Forwarder Election Extensibility
             draft-ietf-bess-evpn-df-election-framework-06

Abstract

   The Designated Forwarder (DF) in EVPN networks is the Provider Edge
   (PE) router responsible for sending broadcast, unknown unicast and
   multicast (BUM) traffic to a multi-homed Customer Equipment (CE)
   device, on a given VLAN on a particular Ethernet Segment (ES). The DF
   is selected out of a list of candidate PEs that advertise the same
   Ethernet Segment Identifier (ESI) to the EVPN network. By default,
   EVPN uses a DF Election algorithm referred to as "Service Carving"
   and it is based on a modulus function (V mod N) that takes the number
   of PEs in the ES (N) and the VLAN value (V) as input. This default DF
   Election algorithm has some inefficiencies that this document
   addresses by defining a new DF Election algorithm and a capability to
   influence the DF Election result for a VLAN, depending on the state
   of the associated Attachment Circuit (AC). In addition, this document
   creates a registry with IANA, for future DF Election Algorithms and
   Capabilities. It also presents a formal definition and clarification
   of the DF Election Finite State Machine.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
 

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Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors. All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents

   1. Conventions and Terminology . . . . . . . . . . . . . . . . . .  3
   2. Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.1. Default Designated Forwarder (DF) Election in EVPN  . . . .  4
     2.2. Problem Statement . . . . . . . . . . . . . . . . . . . . .  5
       2.2.1. Unfair Load-Balancing and Service Disruption  . . . . .  6
       2.2.2. Traffic Black-Holing on Individual AC Failures  . . . .  7
     2.3. The Need for Extending the Default DF Election in EVPN  . .  9
   3. Designated Forwarder Election Protocol and BGP Extensions . . . 10
     3.1 The DF Election Finite State Machine (FSM) . . . . . . . . . 10
     3.2 The DF Election Extended Community . . . . . . . . . . . . . 13
     3.3 Auto-Derivation of ES-Import Route Target  . . . . . . . . . 15
   4. The Highest Random Weight DF Election Type  . . . . . . . . . . 15
     4.1. HRW and Consistent Hashing  . . . . . . . . . . . . . . . . 16